This invention relates to an article transport facility, and more particularly to an article transport facility including an article carrier movable along a track extending by way of an article transfer location corresponding to a storage rack.
Such an article transport facility includes a plurality of article transfer stations arranged along the track. The article carrier moves along the track to transport articles between the stations.
Article racks are provided to store temporarily articles to be transported to the stations. Each article rack is usually located in a retracted position away from the track, not to interfere with movement of the article carrier. The article rack is shifted from the retracted position to an extended position projecting toward the track when an article is stored on the article rack or when an article stored on the article rack is transported therefrom. Then, the article is transferred to or from the article rack.
A conventional article transport facility has a guide rail serving as the track installed on the ceiling. A link mechanism is connected at an upper end thereof connected to the ceiling to be rockable about a horizontal axis for supporting each article rack to be shiftable between the extended position and retracted position. A hydraulic cylinder is disposed between the ceiling and the link mechanism for shifting the article rack between the extended position and retracted position (see JP 10-45213, for example).
In the above article transport facility, the article racks may be arranged back to back adjacent one another in the shifting direction of the article racks, or the article racks and other devices may be arranged adjacent one another in the shifting direction of the article racks. Thus, the installation space for the article racks is required to be as small as possible in the shifting direction of the article racks.
In the conventional article transport facility, however, since each article rack is shifted between the extended position and retracted position by rocking the link mechanism in the shifting direction of the article rack about the horizontal axis, a large space must be secured for allowing the link mechanism to rock in the shifting direction of the article rack. This results in a large installation space of components for shifting the article rack in its shifting direction. Thus, the conventional article transport facility tends to require a large installation space for the article racks in the shifting direction of the article racks.
It is conceivable that the components for shifting the article rack include a fixed guide for supporting and guiding the article rack to be shiftable in the shifting direction. However, in this case also, the fixed guide is required to have a sufficient size for allowing the article rack to shift between the extended position and retracted position. Thus, the fixed guide tends to require a large installation space in the shifting direction of the article rack.